At least the steel is made here, which is the most critical part of the tool. If you hate the handle, chop it off and make your own
Actually, without Mayhew actually stating the COO of the raw steel they use, it's only the forming and finishing of the steel that is done in the USA. The steel could be from anywhere. There are complex rules for determining how different inputs affect the country of origin determination. Mayhew plays it safe by it's claim of global components.
I quickly went through the Mayhew website looking to see if they claimed to use USA made steel for their products but did not find any claims. That's not to say they don't use USA made steel. If I were a manufacturer, unless an essential commodity is only available from one country, I wouldn't want to lock myself into a claim I might have have to change if for some reason my preferred source is unable to deliver the products I need as inputs for my products.
For June 2014, imports constituted 27% the steel market and that was down 11% from the previous month. In some categories of specialty steels, imports make up a huge percentage of the available steel in the USA market.
I like USA made products but Taiwan is a democratic nation that is a friendly partner of the the United States. Trading with countries like Taiwan helps both them and the USA economically.